Automated conversion of two-dimensional hydrology vector models into valid three-dimensional hydrology vector models

ABSTRACT

A system for automated conversion of two-dimensional hydrology vector models into valid three-dimensional hydrology vector models, comprising a vector extraction engine that retrieves vectors from, and sends vectors to, a vector storage, a DSM server that retrieves a DSM from a DSM storage and computes a DSM from stereo disparity measurements of a stereo pair retrieved from a raster storage, and a rendering engine that provides visual representations of images for review by a human user, and a method for automated hydrology vector model development utilizing the system of the invention.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/789,893 titled “AUTOMATED CONVERSION OF TWO-DIMENSIONAL HYDROLOGYVECTOR MODELS INTO VALID THREE-DIMENSIONAL HYDROLOGY VECTOR MODELS”,filed on Jul. 1, 2015, which claims the benefit of, and priority to,U.S. provisional patent application Ser. No. 62/019,878, titled“ENHANCEMENTS FOR AUTOMATED HYDROLOGY MODEL DEVELOPMENT” and filed onJul. 1, 2014, the entire specification of which is incorporated hereinby reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Art

The disclosure relates to the field of image processing and linearfeature extraction, and more particularly to the field of extractingthree-dimensional hydrology vector models from remotely-sensed imagery.

Discussion of the State of the Art

In the art of linear feature extraction, ROADTRACKER™ and similar toolsenable automated bulk extraction and semi-automated point-to-pointextraction of two-dimensional linear feature vectors fromremotely-sensed imagery. Extractions by these tools are image-based,meaning image content automatically influences the trajectories of theextracted vectors. In semi-automated extraction, the image raster isdisplayed in a viewer and extraction is partially guided by user mouseclicks placed along a desired linear feature. Tools like ROADTRACKER™can be used to perform two-dimensional extraction of, among otherthings, single-line drainages (the centerline vectors of narrowstreams), double-line drainages (the two side vectors of rivers), andthe boundaries of water bodies, and includes automatic smoothing of theextracted vectors and automatic topology cleaning of the vectors(elimination of gaps (under-shoots) and dangles (over-shoots) wherevectors are intended to be perfectly incident to one another.) In thismanner, a two-dimensional hydrology vector model for a raster image maybe constructed.

What is needed is an automated way to convert a two-dimensionalhydrology vector model into a corresponding three-dimensional hydrologyvector model where the latter is geometrically consistent with thephysics of real-world hydrology, i.e., lake boundaries are level,corresponding points on opposite sides of a river are at the samealtitude, and water flow is monotone decreasing in altitude.

SUMMARY OF THE INVENTION

Accordingly, the inventor has conceived and reduced to practice, in apreferred embodiment of the invention, a system and method forautomatically converting a two-dimensional hydrology vector model into athree-dimensional hydrology vector model where the latter isgeometrically consistent with the physics of real-world hydrology, i.e.,lake boundaries are level, corresponding points on opposite sides of ariver are at the same altitude, and water flow is monotone decreasing inaltitude. The three-dimensional vectors are expressed in the X, Y, Zcoordinates of object space.

According to a preferred embodiment of the invention, a system forautomatically converting a two-dimensional hydrology vector model into athree-dimensional hydrology vector model that is geometricallyconsistent with the physics of real-world hydrology comprising a vectorserver stored and operating on a network-connected computing device, araster server stored and operating on a network-connected computingdevice, a digital surface model (DSM) server stored and operating on anetwork-connected computing device, a vector extraction engine storedand operating on a network-connected computing device, and a renderingengine stored and operating on a network-connected computing device, isdisclosed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The accompanying drawings illustrate several embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention according to the embodiments. It will beappreciated by one skilled in the art that the particular embodimentsillustrated in the drawings are merely exemplary, and are not to beconsidered as limiting of the scope of the invention or the claimsherein in any way.

FIG. 1 is a block diagram illustrating an exemplary hardwarearchitecture of a computing device used in an embodiment of theinvention.

FIG. 2 is a block diagram illustrating an exemplary logical architecturefor a client device, according to an embodiment of the invention.

FIG. 3 is a block diagram showing an exemplary architectural arrangementof clients, servers, and external services, according to an embodimentof the invention.

FIG. 4 is another block diagram illustrating an exemplary hardwarearchitecture of a computing device used in various embodiments of theinvention.

FIG. 5 is a block diagram illustrating an exemplary system architecturefor automated conversion of two-dimensional hydrology vector models intovalid three-dimensional hydrology vector models, according to apreferred embodiment of the invention.

DETAILED DESCRIPTION

The inventor has conceived in a preferred embodiment of the invention, asystem and method for automatic conversion of two-dimensional hydrologyvector models into three-dimensional hydrology vector models, where thelatter are geometrically consistent with the physical behavior ofreal-world hydrology. The three-dimensional vectors are expressed in theX, Y, Z coordinates of object space.

One or more different inventions may be described in the presentapplication. Further, for one or more of the inventions describedherein, numerous alternative embodiments may be described; it should beappreciated that these are presented for illustrative purposes only andare not limiting of the inventions contained herein or the claimspresented herein in any way. One or more of the inventions may be widelyapplicable to numerous embodiments, as may be readily apparent from thedisclosure. In general, embodiments are described in sufficient detailto enable those skilled in the art to practice one or more of theinventions, and it should be appreciated that other embodiments may beutilized and that structural, logical, software, electrical and otherchanges may be made without departing from the scope of the particularinventions. Accordingly, one skilled in the art will recognize that oneor more of the inventions may be practiced with various modificationsand alterations. Particular features of one or more of the inventionsdescribed herein may be described with reference to one or moreparticular embodiments or figures that form a part of the presentdisclosure, and in which are shown, by way of illustration, specificembodiments of one or more of the inventions. It should be appreciated,however, that such features are not limited to usage in the one or moreparticular embodiments or figures with reference to which they aredescribed. The present disclosure is neither a literal description ofall embodiments of one or more of the inventions nor a listing offeatures of one or more of the inventions that must be present in allembodiments.

Headings of sections provided in this patent application and the titleof this patent application are for convenience only, and are not to betaken as limiting the disclosure in any way.

Devices that are in communication with each other need not be incontinuous communication with each other, unless expressly specifiedotherwise. In addition, devices that are in communication with eachother may communicate directly or indirectly through one or morecommunication means or intermediaries, logical or physical.

A description of an embodiment with several components in communicationwith each other does not imply that all such components are required. Tothe contrary, a variety of optional components may be described toillustrate a wide variety of possible embodiments of one or more of theinventions and in order to more fully illustrate one or more aspects ofthe inventions. Similarly, although process steps, method steps,algorithms or the like may be described in a sequential order, suchprocesses, methods and algorithms may generally be configured to work inalternate orders, unless specifically stated to the contrary. In otherwords, any sequence or order of steps that may be described in thispatent application does not, in and of itself, indicate a requirementthat the steps be performed in that order. The steps of describedprocesses may be performed in any order practical. Further, some stepsmay be performed simultaneously despite being described or implied asoccurring non-simultaneously (e.g., because one step is described afterthe other step). Moreover, the illustration of a process by itsdepiction in a drawing does not imply that the illustrated process isexclusive of other variations and modifications thereto, does not implythat the illustrated process or any of its steps are necessary to one ormore of the invention(s), and does not imply that the illustratedprocess is preferred. Also, steps are generally described once perembodiment, but this does not mean they must occur once, or that theymay only occur once each time a process, method, or algorithm is carriedout or executed. Some steps may be omitted in some embodiments or someoccurrences, or some steps may be executed more than once in a givenembodiment or occurrence.

When a single device or article is described herein, it will be readilyapparent that more than one device or article may be used in place of asingle device or article. Similarly, where more than one device orarticle is described herein, it will be readily apparent that a singledevice or article may be used in place of the more than one device orarticle.

The functionality or the features of a device may be alternativelyembodied by one or more other devices that are not explicitly describedas having such functionality or features. Thus, other embodiments of oneor more of the inventions need not include the device itself

Techniques and mechanisms described or referenced herein will sometimesbe described in singular form for clarity. However, it should beappreciated that particular embodiments may include multiple iterationsof a technique or multiple instantiations of a mechanism unless notedotherwise. Process descriptions or blocks in figures should beunderstood as representing modules, segments, or portions of code whichinclude one or more executable instructions for implementing specificlogical functions or steps in the process. Alternate implementations areincluded within the scope of embodiments of the present invention inwhich, for example, functions may be executed out of order from thatshown or discussed, including substantially concurrently or in reverseorder, depending on the functionality involved, as would be understoodby those having ordinary skill in the art.

Hardware Architecture

Generally, the techniques disclosed herein may be implemented onhardware or a combination of software and hardware. For example, theymay be implemented in an operating system kernel, in a separate userprocess, in a library package bound into network applications, on aspecially constructed machine, on an application-specific integratedcircuit (ASIC), or on a network interface card.

Software/hardware hybrid implementations of at least some of theembodiments disclosed herein may be implemented on a programmablenetwork-resident machine (which should be understood to includeintermittently connected network-aware machines) selectively activatedor reconfigured by a computer program stored in memory. Such networkdevices may have multiple network interfaces that may be configured ordesigned to utilize different types of network communication protocols.A general architecture for some of these machines may be describedherein in order to illustrate one or more exemplary means by which agiven unit of functionality may be implemented. According to specificembodiments, at least some of the features or functionalities of thevarious embodiments disclosed herein may be implemented on one or moregeneral-purpose computers associated with one or more networks, such asfor example an end-user computer system, a client computer, a networkserver or other server system, a mobile computing device (e.g., tabletcomputing device, mobile phone, smartphone, laptop, or other appropriatecomputing device), a consumer electronic device, a music player, or anyother suitable electronic device, router, switch, or other suitabledevice, or any combination thereof. In at least some embodiments, atleast some of the features or functionalities of the various embodimentsdisclosed herein may be implemented in one or more virtualized computingenvironments (e.g., network computing clouds, virtual machines hosted onone or more physical computing machines, or other appropriate virtualenvironments).

Referring now to FIG. 1, there is shown a block diagram depicting anexemplary computing device 100 suitable for implementing at least aportion of the features or functionalities disclosed herein. Computingdevice 100 may be, for example, any one of the computing machines listedin the previous paragraph, or indeed any other electronic device capableof executing software- or hardware-based instructions according to oneor more programs stored in memory. Computing device 100 may be adaptedto communicate with a plurality of other computing devices, such asclients or servers, over communications networks such as a wide areanetwork a metropolitan area network, a local area network, a wirelessnetwork, the Internet, or any other network, using known protocols forsuch communication, whether wireless or wired.

In one embodiment, computing device 100 includes one or more centralprocessing units (CPU) 102, one or more interfaces 110, and one or morebusses 106 (such as a peripheral component interconnect (PCI) bus). Whenacting under the control of appropriate software or firmware, CPU 102may be responsible for implementing specific functions associated withthe functions of a specifically configured computing device or machine.For example, in at least one embodiment, a computing device 100 may beconfigured or designed to function as a server system utilizing CPU 102,local memory 101 and/or remote memory 120, and interface(s) 110. In atleast one embodiment, CPU 102 may be caused to perform one or more ofthe different types of functions and/or operations under the control ofsoftware modules or components, which for example, may include anoperating system and any appropriate applications software, drivers, andthe like.

CPU 102 may include one or more processors 103 such as, for example, aprocessor from one of the Intel, ARM, Qualcomm, and AMD families ofmicroprocessors. In some embodiments, processors 103 may includespecially designed hardware such as application-specific integratedcircuits (ASICs), electrically erasable programmable read-only memories(EEPROMs), field-programmable gate arrays (FPGAs), and so forth, forcontrolling operations of computing device 100. In a specificembodiment, a local memory 101 (such as non-volatile random accessmemory (RAM) and/or read-only memory (ROM), including for example one ormore levels of cached memory) may also form part of CPU 102. However,there are many different ways in which memory may be coupled to system100. Memory 101 may be used for a variety of purposes such as, forexample, caching and/or storing data, programming instructions, and thelike. It should be further appreciated that CPU 102 may be one of avariety of system-on-a-chip (SOC) type hardware that may includeadditional hardware such as memory or graphics processing chips, such asa Qualcomm SNAPDRAGON™ or Samsung EXYNOS™ CPU as are becomingincreasingly common in the art, such as for use in mobile devices orintegrated devices.

As used herein, the term “processor” is not limited merely to thoseintegrated circuits referred to in the art as a processor, a mobileprocessor, or a microprocessor, but broadly refers to a microcontroller,a microcomputer, a programmable logic controller, anapplication-specific integrated circuit, and any other programmablecircuit.

In one embodiment, interfaces 110 are provided as network interfacecards (NICs). Generally, NICs control the sending and receiving of datapackets over a computer network; other types of interfaces 110 may forexample support other peripherals used with computing device 100. Amongthe interfaces that may be provided are Ethernet interfaces, frame relayinterfaces, cable interfaces, DSL interfaces, token ring interfaces,graphics interfaces, and the like. In addition, various types ofinterfaces may be provided such as, for example, universal serial bus(USB), Serial, Ethernet, FIREWIRE™, THUNDERBOLT™, PCI, parallel, radiofrequency (RF), BLUETOOTH™, near-field communications (e.g., usingnear-field magnetics), 802.11 (Wi-Fi), frame relay, TCP/IP, ISDN, fastEthernet interfaces, Gigabit Ethernet interfaces, Serial ATA (SATA) orexternal SATA (ESATA) interfaces, high-definition multimedia interface(HDMI), digital visual interface (DVI), analog or digital audiointerfaces, asynchronous transfer mode (ATM) interfaces, high-speedserial interface (HSSI) interfaces, Point of Sale (POS) interfaces,fiber data distributed interfaces (FDDIs), and the like. Generally, suchinterfaces 110 may include physical ports appropriate for communicationwith appropriate media. In some cases, they may also include anindependent processor (such as a dedicated audio or video processor, asis common in the art for high-fidelity A/V hardware interfaces) and, insome instances, volatile and/or non-volatile memory (e.g., RAM).

Although the system shown in FIG. 1 illustrates one specificarchitecture for a computing device 100 for implementing one or more ofthe inventions described herein, it is by no means the only devicearchitecture on which at least a portion of the features and techniquesdescribed herein may be implemented. For example, architectures havingone or any number of processors 103 may be used, and such processors 103may be present in a single device or distributed among any number ofdevices. In one embodiment, a single processor 103 handlescommunications as well as routing computations, while in otherembodiments a separate dedicated communications processor may beprovided. In various embodiments, different types of features orfunctionalities may be implemented in a system according to theinvention that includes a client device (such as a tablet device orsmartphone running client software) and server systems (such as a serversystem described in more detail below).

Regardless of network device configuration, the system of the presentinvention may employ one or more memories or memory modules (such as,for example, remote memory block 120 and local memory 101) configured tostore data, program instructions for the general-purpose networkoperations, or other information relating to the functionality of theembodiments described herein (or any combinations of the above). Programinstructions may control execution of or comprise an operating systemand/or one or more applications, for example. Memory 120 or memories101, 120 may also be configured to store data structures, configurationdata, encryption data, historical system operations information, or anyother specific or generic non-program information described herein.

Because such information and program instructions may be employed toimplement one or more systems or methods described herein, at least somenetwork device embodiments may include nontransitory machine-readablestorage media, which, for example, may be configured or designed tostore program instructions, state information, and the like forperforming various operations described herein. Examples of suchnontransitory machine-readable storage media include, but are notlimited to, magnetic media such as hard disks, floppy disks, andmagnetic tape; optical media such as CD-ROM disks; magneto-optical mediasuch as optical disks, and hardware devices that are speciallyconfigured to store and perform program instructions, such as read-onlymemory devices (ROM), flash memory (as is common in mobile devices andintegrated systems), solid state drives (SSD) and “hybrid SSD” storagedrives that may combine physical components of solid state and hard diskdrives in a single hardware device (as are becoming increasingly commonin the art with regard to personal computers), memristor memory, randomaccess memory (RAM), and the like. It should be appreciated that suchstorage means may be integral and non-removable (such as RAM hardwaremodules that may be soldered onto a motherboard or otherwise integratedinto an electronic device), or they may be removable such as swappableflash memory modules (such as “thumb drives” or other removable mediadesigned for rapidly exchanging physical storage devices),“hot-swappable” hard disk drives or solid state drives, removableoptical storage discs, or other such removable media, and that suchintegral and removable storage media may be utilized interchangeably.Examples of program instructions include both object code, such as maybe produced by a compiler, machine code, such as may be produced by anassembler or a linker, byte code, such as may be generated by forexample a Java™ compiler and may be executed using a Java virtualmachine or equivalent, or files containing higher level code that may beexecuted by the computer using an interpreter (for example, scriptswritten in Python, Perl, Ruby, Groovy, or any other scripting language).

In some embodiments, systems according to the present invention may beimplemented on a standalone computing system. Referring now to FIG. 2,there is shown a block diagram depicting a typical exemplaryarchitecture of one or more embodiments or components thereof on astandalone computing system. Computing device 200 includes processors210 that may run software that carry out one or more functions orapplications of embodiments of the invention, such as for example aclient application 230. Processors 210 may carry out computinginstructions under control of an operating system 220 such as, forexample, a version of Microsoft's WINDOWS™ operating system, Apple's MacOS/X or iOS operating systems, some variety of the Linux operatingsystem, Google's ANDROID™ operating system, or the like. In many cases,one or more shared services 225 may be operable in system 200, and maybe useful for providing common services to client applications 230.Services 225 may for example be WINDOWS™ services, user-space commonservices in a Linux environment, or any other type of common servicearchitecture used with operating system 210. Input devices 270 may be ofany type suitable for receiving user input, including for example akeyboard, touchscreen, microphone (for example, for voice input), mouse,touchpad, trackball, or any combination thereof. Output devices 260 maybe of any type suitable for providing output to one or more users,whether remote or local to system 200, and may include for example oneor more screens for visual output, speakers, printers, or anycombination thereof. Memory 240 may be random-access memory having anystructure and architecture known in the art, for use by processors 210,for example to run software. Storage devices 250 may be any magnetic,optical, mechanical, memristor, or electrical storage device for storageof data in digital form (such as those described above, referring toFIG. 1). Examples of storage devices 250 include flash memory, magnetichard drive, CD-ROM, and/or the like.

In some embodiments, systems of the present invention may be implementedon a distributed computing network, such as one having any number ofclients and/or servers. Referring now to FIG. 3, there is shown a blockdiagram depicting an exemplary architecture 300 for implementing atleast a portion of a system according to an embodiment of the inventionon a distributed computing network. According to the embodiment, anynumber of clients 330 may be provided. Each client 330 may run softwarefor implementing client-side portions of the present invention; clientsmay comprise a system 200 such as that illustrated in FIG. 2. Inaddition, any number of servers 320 may be provided for handlingrequests received from one or more clients 330. Clients 330 and servers320 may communicate with one another via one or more electronic networks310, which may be in various embodiments any of the Internet, a widearea network, a mobile telephony network (such as CDMA or GSM cellularnetworks), a wireless network (such as Wi-Fi, Wimax, LTE, and so forth),or a local area network (or indeed any network topology known in theart; the invention does not prefer any one network topology over anyother). Networks 310 may be implemented using any known networkprotocols, including for example wired and/or wireless protocols.

In addition, in some embodiments, servers 320 may call external services370 when needed to obtain additional information, or to refer toadditional data concerning a particular call. Communications withexternal services 370 may take place, for example, via one or morenetworks 310. In various embodiments, external services 370 may compriseweb-enabled services or functionality related to or installed on thehardware device itself. For example, in an embodiment where clientapplications 230 are implemented on a smartphone or other electronicdevice, client applications 230 may obtain information stored in aserver system 320 in the cloud or on an external service 370 deployed onone or more of a particular enterprise's or user's premises.

In some embodiments of the invention, clients 330 or servers 320 (orboth) may make use of one or more specialized services or appliancesthat may be deployed locally or remotely across one or more networks310. For example, one or more databases 340 may be used or referred toby one or more embodiments of the invention. It should be understood byone having ordinary skill in the art that databases 340 may be arrangedin a wide variety of architectures and using a wide variety of dataaccess and manipulation means. For example, in various embodiments oneor more databases 340 may comprise a relational database system using astructured query language (SQL), while others may comprise analternative data storage technology such as those referred to in the artas “NoSQL” (for example, Hadoop Cassandra, Google BigTable, and soforth). In some embodiments, variant database architectures such ascolumn-oriented databases, in-memory databases, clustered databases,distributed databases, or even flat file data repositories may be usedaccording to the invention. It will be appreciated by one havingordinary skill in the art that any combination of known or futuredatabase technologies may be used as appropriate, unless a specificdatabase technology or a specific arrangement of components is specifiedfor a particular embodiment herein. Moreover, it should be appreciatedthat the term “database” as used herein may refer to a physical databasemachine, a cluster of machines acting as a single database system, or alogical database within an overall database management system. Unless aspecific meaning is specified for a given use of the term “database”, itshould be construed to mean any of these senses of the word, all ofwhich are understood as a plain meaning of the term “database” by thosehaving ordinary skill in the art.

Similarly, most embodiments of the invention may make use of one or moresecurity systems 360 and configuration systems 350. Security andconfiguration management are common information technology (IT) and webfunctions, and some amount of each are generally associated with any ITor web systems. It should be understood by one having ordinary skill inthe art that any configuration or security subsystems known in the artnow or in the future may be used in conjunction with embodiments of theinvention without limitation, unless a specific security 360 orconfiguration system 350 or approach is specifically required by thedescription of any specific embodiment.

FIG. 4 shows an exemplary overview of a computer system 400 as may beused in any of the various locations throughout the system. It isexemplary of any computer that may execute code to process data. Variousmodifications and changes may be made to computer system 400 withoutdeparting from the broader scope of the system and method disclosedherein. CPU 401 is connected to bus 402, to which bus is also connectedmemory 403, nonvolatile memory 404, display 407, I/O unit 408, andnetwork interface card (NIC) 413. I/O unit 408 may, typically, beconnected to keyboard 409, pointing device 410, hard disk 412, andreal-time clock 411. NIC 413 connects to network 414, which may be theInternet or a local network, which local network may or may not haveconnections to the Internet. Also shown as part of system 400 is powersupply unit 405 connected, in this example, to ac supply 406. Not shownare batteries that could be present, and many other devices andmodifications that are well known but are not applicable to the specificnovel functions of the current system and method disclosed herein. Itshould be appreciated that some or all components illustrated may becombined, such as in various integrated applications (for example,Qualcomm or Samsung SOC-based devices), or whenever it may beappropriate to combine multiple capabilities or functions into a singlehardware device (for instance, in mobile devices such as smartphones,video game consoles, in-vehicle computer systems such as navigation ormultimedia systems in automobiles, or other integrated hardwaredevices).

In various embodiments, functionality for implementing systems ormethods of the present invention may be distributed among any number ofclient and/or server components. For example, various software modulesmay be implemented for performing various functions in connection withthe present invention, and such modules may be variously implemented torun on server and/or client components.

Conceptual Architecture

FIG. 5 is a block diagram illustrating an exemplary system architecture500 for automatically converting a two-dimensional hydrology vectormodel into a three-dimensional hydrology vector model that isgeometrically consistent with the physics of real-world hydrology, andviewing the results, according to a preferred embodiment of theinvention. According to the embodiment, a vector extraction engine 501may retrieve vectors from, and send vectors to, a vector storage such asa vector database 502 or other data storage means (such as, for example,integral or removable hardware-based storage such as a hard disk drive,or software-based storage schema common in the art); a raster database503 may provide raster images from a raster storage, for example such assatellite images or similar raster image data that depict an actualphysical environment; a DSM server 508 may retrieve a DSM from a DSMstorage 507, or may compute a DSM from the stereo disparity measurementsof a stereo pair retrieved from a raster storage. Retrievedtwo-dimensional vectors and DSM may be provided to a vector extractionengine 501, which lifts the vectors into three dimensions and enforcesgeometric constraints, making the latter vectors consistent with thephysics of real-world hydrology.

Vectors, rasters, and DSM may then be provided to a rendering engine504, that may form a combined visualization, showing how the vectorsrelate to the rasters or DSM, such as may be presentable on a viewer 506such as a display screen, for example, for review by a human user.Additionally, a user may interact with the presented visualization usinga variety of input devices 505 such as (for example, including but notlimited to) a computer mouse or keyboard to manipulate the visualization(e.g., zoom or pan). The three-dimensional extracted vectors may befurther provided to vector extraction engine 501, for example, to storethe vectors for future reference.

It should be appreciated that according to the embodiment, various meansof connection or communication between the components of a system 500may be utilized according to the invention interchangeably orsimultaneously, such as for example a direct, physical data connection(such as via a data cable or similar physical means), a software-basedconnection such as via an application programming interface (API) orother software communication means (such as may be suitable, forexample, in arrangements where multiple system components may operate ona single hardware device such as a computing server or workstation), orany of a variety of network connections such as via the Internet orother data communications network. It should therefore be appreciatedthat the connections shown are exemplary in nature and represent only aselection of possible arrangements, and that alternate or additionalconnections may be utilized according to the invention.

Detailed Description of Exemplary Embodiments

The vector extraction engine takes as input a two-dimensional hydrologyvector model (expressed in the X, Y coordinates of object space) and aDSM (expressed in the X, Y, Z coordinates of object space) and computesa three-dimensional hydrology vector model (expressed in the X, Y, Zcoordinates of object space) that is geometrically consistent with thephysics of real-world hydrology, namely: lake boundaries are level,corresponding points on opposite sides of a river are at the samealtitude, and water flow is monotone decreasing in altitude.

In a preferred embodiment, the vector extraction engine firstautomatically projects all two-dimensional hydrology vectors vertically(in the Z direction) to the DSM. Care is taken to ensure that theinter-connection topology among the vectors that existed in twodimensions is maintained in the three-dimensional projection.

For each two-dimensional lake boundary vector, in a preferredembodiment, the vector extraction engine takes median Z-value of theinitially projected lake boundary vector as the common Z-value for allthe points of the final three-dimensional lake boundary vector. Anythree-dimensional vectors that were initially incident to the projectedlake boundary vector are automatically adjusted near their terminals tomaintain the incidence with the final three-dimensional lake boundaryvector.

For any pair of two-dimensional side vectors U and V of a river, in apreferred embodiment, the vector extraction engine automaticallycomputes the two-dimensional centerline vector W between U and V, andthen automatically projects W vertically (in the Z direction) to the DSMresulting in the three-dimensional vector W*. Let S_(W) denote theunique infinite vertical surface containing W. Similarly define S_(U)and S_(V). The vector extraction engine automatically takes theprojected vector W* and projects it normally from surface S_(W) ontosurfaces S_(U) and S_(V). These new vectors on S_(U) and S_(V) are takenas the final three-dimensional vectors corresponding to U and V,respectively. Any three-dimensional vectors that were incident to theinitial projections of U and V are automatically adjusted near theirterminals to maintain the incidence with the final three-dimensionalversions of U and V.

Let W* denote a projected (three-dimensional) single-line drainagevector. Let p and q denote the endpoints of W*, where the Z-value of pis greater than that of q. To enforce monotonicity of Z-profile on W*,in a preferred embodiment, the vector extraction engine employs one ofseveral existing known algorithms to create a new vector W** from p to qthat is monotone decreasing in Z and as close as possible to W*according to some measure of closeness. These algorithms will be knownto someone familiar in the art. The vector extraction engineautomatically indicates (perhaps by depicting an arrow on the resultingvector in the viewer) that the drainage direction goes from endpoint p(with higher Z-value) to endpoint q (with lower Z-value).

In a preferred embodiment, the vector extraction engine automaticallyaffects the transformation from W* to W** (as described previously) forthe two-dimensional centerline vector W of a river, whosetwo-dimensional side vectors are denoted U and V, before constructingthe final three-dimensional versions of U and V (as describedpreviously). In other words, the three-dimensional versions of U and Vare constructed from W** instead of W*.

Finally in a preferred embodiment, the vector extraction engine smoothsall three-dimensional single-line and double-line drainage vectors inthe Z coordinate.

The skilled person will be aware of a range of possible modifications ofthe various embodiments described above. Accordingly, the presentinvention is defined by the claims and their equivalents.

What is claimed is:
 1. A system for automated conversion oftwo-dimensional hydrology vector models into valid three-dimensionalhydrology vector models, comprising: a computing device comprising aprocessor, a memory, and a plurality of programming instructions storedin the memory and operable on the processor, wherein the plurality ofprogramming instructions, when operating on the processor, cause theprocessor to execute: a hydrology vector server configured to retrievevectors from, and send vectors to, a vector storage such as a vectordatabase; a digital surface model server configured to compute a digitalsurface model from stereo disparity measurements of a stereo image pairretrieved from a raster storage; a rendering engine configured togenerate a visual representation in the form of three-dimensionalhydrology vector model by projecting a two-dimensional hydrology vectormodel onto the digital surface model.
 2. The system of claim 1, furthercomprising a viewer device adapted to receive information from othercomponents of the system and present the information for review by ahuman user.
 3. The system of claim 1, further comprising a plurality ofinput devices adapted to receive input from a human user and provide theresults of the input to other components of the system.
 4. A method forautomated three-dimensional hydrology model development, comprising thesteps of: receiving, at a hydrology vector server, a plurality of inputimages; extracting a plurality of two-dimensional hydrology vectors fromat least a portion of the plurality of input images; computing a digitalsurface model from stereo disparity measurements of a stereo image pairretrieved from the plurality of input images; and computing athree-dimensional hydrology vector model by projecting thetwo-dimensional hydrology vectors onto the digital surface model.